Reprocessing methods include one used at Oak Ridge National Laboratory referred to as the "bomb reduction" method. It involves a laborious sequence of operations of hydrofluorination of the oxide to the fluoride and reduction of the fluoride to metal with calcium and magnesium. The separation of the uranium metal from the reaction products is expensive and disposal of these reaction products in accordance with governmental regulations is difficult and costly. In addition, the hydrofluorination process presents significant safety hazards.
Another similar process first converts uranium oxide to uranium hydride, which, after magnetically separating from the other reaction products, is then converted to uranium metal. The separation process is determining for the uranium metal yield, limiting the results to insignificant amounts.
Other processes utilize molten salt solutions. In one, uranium oxide is reduced to uranium metal with magnesium in a solution of magnesium and halide salts. In another, a process similar to a solvent extraction is used where the solvent is a molten alloy and the extractant is a mixture of molten salts. Products of these molten salt processes must be separated from the excess starting material and by-products in the molten state. Both processes are carried out in a nonaqueous environment.
In view of the limited yields, the unsafe conditions, and the difficulty of separating the products when using the presently known processes, it is necessary to find an alternative process that will allow easier isolation of products using less hazardous reagents.